Capacitive inductive winding

ABSTRACT

An improved capacitive inductive winding is disclosed for use with devices requiring an inductance and a series or shunt capacitance. The disclosed invention is a high reactance winding having a nearly uniform current density within the conductive foils, and having a substantially increased capacitance and voltampere capacity over the prior art. The invention is suitable for use with devices requiring a high starting voltage and a constant wattage operation such as gaseous discharge devices. The invention is also applicable for use with voltage and wattage regulators, ballasts and ferro-resonant transformers. The foregoing abstract is merely a resume of one general application, is not a complete discussion of all principles of operation or applications, and is not to be construed as a limitation on the scope of the claimed subject matter.

Szatmari 3,688,232 [4 1 Aug. 29, 1972 CAPACITIVE INDUCTIVE WINDING [72]Inventor: Gabor' Szatmari, 190 Bartley Bull Parkway, Brampton, Ontario,Canada [22] Filed: Feb. 16, 1971 [21] Appl. No.: 115,479

[52] US. Cl. ..336/69, 336/180, 336/223 [51] Int. Cl ..H01f 15/14 [58]Field of Search ..336/69, 180, 70, 182, 183, 336/223 [56] ReferencesCited UNITED STATES PATENTS 3,210,706 10/1965 Book... ..336/69'X3,078,411 2/1963 Book ..336/69 UX 3,210,704 10/1965 Book ..336/69 X3,210,705 10/1965 Lockie ..336/69 X 3,209,241 9/1965 Book et al ..336/70X 2,521,513 9/1950 Gray ..336/183 X 3,210,703 10/1965 bockie ..336/69 XPrimary Examiner-Thomas J. Kozma Attorney-Woodlihg, Krost, Granger &Rust ABSTRACT An improved capacitive inductive winding is disclosed foruse with devices requiring an inductance and a series or shuntcapacitance. The disclosed invention is a high reactance winding havinga nearly uniform current density within the conductive foils, and havinga 28 Claims, 8 Drawing figures Patented Aug. 29, 1972 3,688,232

2 Sheets-Sheet 1- PRIOR ART PRIOR- ART Fig. 3

- PE/OQ A127 mvsmozz 64502 EZATMQE/ "Fig5- "'B'Y "0 ZM ATTOIENEV dPatented Aug. 29, 1972 2 Sheets-Shee 2 R we, m% w NM 2 my m 2 0 5 AH BCAPACITIVE INDUCTIVE WINDING BACKGROUND OF THE INVENTION Constantwattage transformers suitable to start and operate gaseous devices havelong been in use. The most primitive of these devices were combinationsof high reactance transformers with one or more external capacitorsarranged in series, parallel or series-parallel.

The next advancement in the art of high reactance transformers was theadvent of the integrated transformers. In the integrated transformers,the capacitance of the secondary circuit is no longer an externalcomponent but an integral part of the transformer secondary coil byinterleaved foils. However, in these integrated transformers, thecapacitive inductive windings do not generate internal heat in the samemanner as a conventional transformer winding. In a conventionaltransformer winding with a wire conductor, the current density isuniform throughout the winding. This results in a uniform heating ofthat winding.

In a capacitive inductive winding, the winding usually consists of twoor more conductive foils separated by the same number of dielectricsheets. The current density is not uniform from one end of a given foilto the other. This non-uniformity is caused by displacement currentsthrough the dielectric that transfer capacitive current from a givenfoil to an adjacent foil along the length of the foil.

The final advancement in the development of high reactance windings wasto reinforce the winding by paralleling two or more layers of foil inareas where the larger current required more cross-sectional area. Thisadvancement produced a more uniform current density through the foil butdid not increase the capacitance of the winding over the prior art. Inaddition, this method of producing a high reactance winding is adifficult task with available coil winding equipment.

Accordingly, an object of the invention is to provide a capacitiveinductive winding with a nearly uniform current density to the inputs ofthe sections of each of the foils. I

Another object of the invention is to provide a capacitive inductivewinding with more uniform inter-' nal heat production.

Another object of the invention is to provide a capacitive inductivewinding which has an increased capacitance over the prior art.

Another object of the invention is to produce a capacitive inductivewinding using a minimum amount of foil thus reducing material costs.

Another object of the invention is to produce a capacitive inductivewinding which is less in weight and size than the prior art windingswith the same volt-ampere capacity.

Another object of the invention is to produce a capacitive inductivewinding which is easy to wind on existing winding equipment.

SUMMARY OF THE INVENTION The invention may be incorporated in acapacitive inductive winding, comprising in combination, first andsecond foil means each having first and second end sections, meansestablishing a larger current carrying ability at said first endsections than at said second end sections of each of said first andsecond foil means, and graded capacitance means establishing a largercapacitance between said first end sections of said first BRIEFDESCRIPTION OF THE DRAWING end sections FIG. 1 is a cross-sectional viewof a prior art capacitive inductive winding;

FIG. 2 is a schematic diagram of the prior art winding as shown in FIG.1;

FIG. 3 is a cross-sectional view of the preferred embodiment of theinvention of a capacitive inductive winding;

FIG. 4 is a schematic diagram of the preferred embodiment of FIG. 3;

FIG. 5 is a schematic diagram of a prior art winding divided into threesections;

FIG. 6 is a schematic diagram of a winding divided into three sectionsand which incorporates the invention;

FIG. 7 is a schematic diagram of a capacitive inductive winding which isan extension of the invention shown in FIG. 4;

FIG. 8 is a schematic diagram of a constant wattage transformerincorporating the present invention.

DESCRIPTION OF DRAWINGS heavy sections 10 and 14 are connected toterminals 16 and 17, respectively.

FIG. 2 is a schematic diagram of the winding shown 'in FIG. 1. The heavysections 10 and 14 and thelight sections 11 and 13 are shown as coils inthis figure toillustrate their inductive property. The phantomcapacitors 18, 19, 20 and 21 illustrate the capacitance inherentlyformed by the foils separated by a dielectric, not shown. capacitances18 and 19 are formed when the first and second foils 8 and 9 are inparallel planes and are separated by a dielectric. When this combinationis rolled into the form of a coil, the additional capacitances 20 and 21are created between adjacent windings. In the usual winding, there aremany turns on the sections 10-13 and 11-14, but only one turn is shownin FIG. 1, for simplicity. The first and second foils are nowinterleaved forming the additional capacitances 20 and 21. Prior artpatents may show in their embodiments just the equivalent capacitance ofcapacitors 18 and 19. However, it is clear from FIG. 1, thatcapacitances 20 and 21 are formed as soon as foils 8 and 9 areinterleaved by rolling the combination into a coil. In this description,all capacitances formed by foils 8 and 9 are considered and it isconceded that the prior art patents have established four capacitancesbetween foils 8 and 9 as shown in FIG. 2.

At a given instant, the current will flow into terminal 16 and out ofterminal 17. It is clear from Kirchhoffs law that one-half of thecurrent into the capacitive circuit at terminal 16 will be transferredby capacitances l8 and 20. The remaining current will be transferred bycapacitances 19 and 21. Sections 10 and 14 must be able to accommodatethe total current into terminal 16, whereas sections 11 and 13 need onlybe able to carry one-half of the current into terminal 16. The prior arthas made an economical use of the foil material by making sections 10and 14 of a larger cross-sectional area than sections 11 and 13.

FIG. 3 shows a basic form of the preferred embodiment of the presentinvention. The capacitive inductive winding has two terminals 36 and 37which are each connected to a foil 33, 34, respectively. Each foil isdivided into two sections. Foil 33 is illustrated by the sec tionmarkings whereas foil 34 is illustrated by the symbol of elevation formetals. Terminal 36 is connected to two branch sections 25 and 26 whichare in parallel with one another. The branch sections 25 and 26 of foil33 are connected to a section 29 at a connection point 31. Sections 25,26 and 29 are the constituents of foil 33. Terminal 37 is connected toparallel branches 27 and 28. These branch sections are connected toanother section 30 with a jumper 32. Sections 27, 28 and 30 form thefoil 34. FIG. 3 shows that branches 25 and 26 are interwoven withbranches 27 and 28. The branch sections 25-28 are also separated bydielectric sheets, not shown for clarity, to increase the capacitance.Since additional foil was required to adequately accommodate the highercurrent flow in these sections, parallel foils are used instead of -asingle thick foil. The branches are interwoven to take advantage of theincreased surface area associated with the required increasedcross-sectional area.

FIG. 4 shows a schematic diagram of the capacitive inductive windingshown in FIG. 3. In this diagram, the branch sections 25, 26, 27 and 28and the sections 29 and 30 are shown as coils to indicate theirinductive property. Capacitances 38 and 39 are formed by interweavingbranches 25, 27 26 and 28. Capacitance 40 is formed by sections 29 and30. When this combination is rolled into a form of a coil, foils 33 and34 are interleaved and capacitances 41, 42 and 43 appear in a mannersimilar to capacitances and 21 in FIG. 2. The invention in FIG. 4 hasestablished six capacitances whereas the prior art winding in FIG. 2

has established only four capacitances. The additional capacitances areobtained by branching parallel sections of thin foils instead of using asingle thick foil as in the prior art.

This capacitance inductive winding shown in FIGS. 3 and 4, not only hasa nearly uniform current density through the foils, as did the prior artwinding shown in FIG. 1, but it also has an increased capacitance usingthe same quantity of foil. This invention takes advantage of the factthat a larger cross-sectional area is required at one end of a foil thanat the other end. The invention utilizes the larger cross-sectional arearequired at one end of the foil to produce a larger surface area at thatend of the foil. This larger surface area will greatly increase thecapacitance of the winding without a material increase in conductorcosts. Therefore, the invention lies in the effective use of theadditional foil required for the higher current at the terminals of thefoils.

The winding shown in FIG. 3 has several possible applications. First ofall, the winding can be used as a passive device such as a ballast. As apassive'device, terminals 36 and 37 become energizing terminals andreceive power from an external source. Secondly, the winding can be usedas an active device when placed within a varying magnetic field. Underthese conditions, terminals 36 and 37 become output terminals to deliverpower to an external load. Thus, the winding can form part of a voltageor wattage regulator. The winding can also be used in a ferro-resonanttransformer by connecting terminals 36 and 37 by a jumper. In this case,current circulates within the winding limited by the capacitivereactance of capacitances 38-43.

FIG. 5 shows a capacitive inductive winding of the prior art having twofoils 49 and 50 andbeing composed of six sections. Sections 51 and 52are heavy conductors as illustrated by the three coils in parallel.Sections 55 and 56 are composed of light conductors as illustrated bythe single coil. Sections 53 and 54 are of intermediate thickness andare illustrated by two coils connected in parallel. Section 51 of foil49 is connected to terminal 58 of the load 57 and section 52 of foil 50is connected to load terminal 59. Sections 51 and 56 lie adjacent eachother, sections 53 and 54 lie adjacent each other and sections 55 and 52lie adjacent each other. Capacitor 60 illustrates the capacitanceestablished between sections 51 and 56. This capacitor represents boththe capacitance formed when sections 51 and 56 lie in parallel planesseparated by a dielectric and the capacitance that is formed when thefoils are interleaved by rolling the layers into a coil. Capacitor 61illustrates the total capacitance established between sections 53 and54. Similarly, capacitor 62 illustrates the total capacitanceestablished between sections 52 and 55.

At a given instant, the current in the circuit flows in a clockwisedirection as illustrated by the arrow. At this instant, a voltage V willbe found across the load. This.

voltage is produced by the induced voltages across each of the sixsections from a primary winding, not

shown, due to the action of the magnetic core 63. Since each of thesections are of the same number of turns, each section produces V,volts. Therefore, the potentials at voltage points 64, 65 and 66 will beV,, 2V, and 3V,, respectively. The potential at voltage point .67 is Vvolts since there is a direct connection between voltage point 67 andload terminal 59. The potential at voltage point 68 will then be V -V,.Similarly, the potentials at voltage points 69 and 70 will be V 2V,

and V 3V,, respectively. The potential across capaciper section.Sections and 76 have only one coil and represent light conductors.

There are three difi'erences between the invention shown in FIG. 6 andthe prior art of FIG. 5. First, the

1 5 heavy conductor sections 71 and 72 lie adjacent to each other. Thesecond difference is the presence of dielectrics, not shown, betweeneach of the branch coils. The third difference lies in the fact that thebranch coils are interwoven as well as being interleaved. Section 72 isdirectly connected to load terminal 83 and section 71 is connected toload terminal 84. In contrast to FIG. 5, the branch coils of sections 71and 72 are interwoven, as in FIG. 4, but not shown for sake ofsimplicity in FIG. 6, establishing the capacitances 86, 87 and 88. Thebranch coils of sections 73 and 74 are likewise interwoven establishingtwo capacitances illustrated as capacitances 89 and 90. Sections 75 and76 only establish a single capacitance 91 in a similar manner to thesingle capacitances 60, 61 and 62 in FIG. 5. If the capacitance 60established between sections 51 and 56 of FIG. 5 is given a value of C,then the capacitances established between sections 53-54 and 55-52 ofFIG. 5 and sections 75-76 of FIG. 6, all have the same capacitance valueof C. The capacitance established between sections 73-74 in FIG. 6 has avalue of 2C, because the surface area with dielectric therebetween istwice as large. Finally, the capacitance established between sections71-72 of FIG. 6 has a value of 3C. There is a total capacitance of 6C inFIG. 6 whereas the total capacitance of the prior art winding in FIG. 5is only 3C.

At a given instant, current through the circuitwill flow in a clockwisedirection as indicated by the arrow. At that instant, the voltage foundacross the load is V,,. The The voltages at terminal 84 and 83 will bezero and V respectively. Each of the sections in FIG. 6 is assumed tohave the same number of turns and will, therefore, have the same voltageinduced when acted upon by a changing flux in a magnetic core 63. Thepotentials at voltage points 95, 96 and 97 will be V 2V, and 3V,. Thepotential at voltage point 98 is V since it'is directly connected toterminal 83 of the load.

Voltage terminals 99 and 100 will be at a potential of Vr-V Voltageterminals 101 and 102 will be at a potential of VI,"2VI and voltageterminal 103 will be at a potential of V1.-3V1.. Whereas the sixsections in Fig. 5 produced three uniform capacitances each having thesame voltage across the capacitances, the six: sections in FIG. 6produce three unequal groups of capacitances each having differentvoltages across them. The voltage across capacitances 86, 87 and 88 islower in value than thevoltage across capacitances 89, 90 and 91.Consequently, a thinner dielectric can be used to separate theinterweaved sections 71- 72. The reduction in dielectric thicknessincreases the capacitance of section 7172. The voltage acrosscapacitances 89 and 90 is a lower value than the voltage acrosscapacitance 91. The dielectric thickness in sections 73-74 can bereduced to increase the capacitance of this section. Therefore, sections7l72 will have three times the capacitive area as sections 75-76 and thelowest potential. difference and the thinnest dielectric of any of thesection pairs. Sections 73-74 will have twice the capacitive area ofsections 75-76. The voltage and the dielectric thickness of sections73-74 will be greaterv than sections 71-72 but less than sections 75-76.Section 75-76 has the lowest surface area, the highest voltage and thethickest dielectric. The result is a capacitive inductive winding with ahigher volt-ampere- The current transferred from each of sections 71, 73

and 75 of foil 78 is not uniform as was the case in the winding shown inFIG. 5. However, the progression of three parallel coils in section 71to two parallel coils in section 73 to a single coil in section 75 withthe proper dielectric thickness in each section, results in a goodapproximation for input cross-sectional area to yield a substantiallyuniform input current density. The uniform input current density was theobjective of the prior art capacitive inductor winding shown in FIG. 5.The invention shown in FIG. 6, yields a substantially uniform inputcurrent density in addition to having an increase in capacitance andvolt-ampere capacity. A

FIG. 7 shows an extension of the principle or the invention shown inFIG. 4. ,The winding consists of two foils 151 and 152 which are eachdivided into (S) sections. Foil 151 has (S) odd number integer sections.whswa siltilhasQ) sxs n im rssr e tion 7 At a given instant, currentwill flow into terminal 153 and out of terminal 154. Sections (1) and(2) must be capable of accommodating all the current flow throughterminal 153. Therefore, sections (1) and (2) are composed of (S)parallel coils. Since sections (1) and (2) are capacitively coupled asillustrated by capacitor 155, a portion of the current into section (1)is transferred into section (2). In order to have a similar value ofinput current density into sections (3) and (4) as the input currentdensity into sections (1) and (2), sections (3) and (4) require only(S-l) parallel coils. Again a portion of the input current istransferred from section (3) to section (4) through capacitance 156.Since the current is again reduced, sections (5) and (6) require only(S-2) parallel coils. The series continues in a similar manner as shownby the dotted lines 168 and 169 until only one coil remains as shown insections (ZS-1) and (28). The sections in FIG. 7 having an equal numberof parallel coils are interwoven as shown in FIG. 4, but represented bycapacitances 155, 156, 157 and 158 for simplicity. Foils 151 and 152 arestill in srl stsd whs uhq silsarsrs lsd ia as il Assuming that eachparallel coil has the same crossscetional area, the current density tothe input of each section can be made substantially the same by the,proper selection of dielectric thickness. Thus, the

dielectric 171A will be the thinnest between the parallel coils ofsections (1) and (2). A thicker dielectric 171B must be used betweensections (3) and (4), and additional thickness dielectric 171C must beused between sections (5) and (6). The thickest dielectric 171E will berequired between the final sections 25 and a nearly as thick dielectric171D between sections (ZS-1). When a capacitive inductive winding isproduced in this manner, a substantial increase in capacitance isachieved over the prior art method of winding using the same quantity offoil.

The progression of parallel coils shown in FIGS. 4, 6, and 7 is not theonly possible configuration in which parallel coils can be connected.FIG. 8 shows a winding having five parallel coils in the first endsections 178 and 179 and a single coil in the second end sections 180and 181. Many additional configurations are possible by adjusting thedielectric in each section pair. This adjustment of the dielectric isnot limited to changes in dielectric thickness alone. The use ofdifferent types of dielectrics with different dielectric constantswithin the same winding is equally applicable to this invention. Thevarious possible parallel coil sequences, changes in dielectricthickness, and a plurality of types of dielectrics used within a windingare all within the scope of this invention.

The variation in dielectric constant K, the dielectric thickness D andvariation in the area A, to achieve a graded capacitance, follows thetextbook formula for capacitance C KA/D FIG. 8 is a schematic diagram ofa constant wattage transformer circuit which incorporates the presentinvention. The circuit is suitable for starting and operating gaseousdischarge devices with negative resistance. These discharge devices suchas fluorescent lamps, mercury vapor lamps, and sodium vapor lamps,require substantially higher starting voltage than operating voltage.Discharge devices have a high impedance before starting and require ahigh voltage for ionization. After being ionized, the impedance of thesedevices drops to a very low value.

In the transformer circuit shown in FIG. 8, a magnetic flux is inducedinto a core 175 by action of a primary winding 177. A magnetic shunt 176permits the secondary voltage to be high at open circuit and yet drop toa low value under normal operating conditions. The magnetic flux in thecore 175 induces voltage into a first and a second foil 194 and 195,respectively. The first foil 194 is composed of sections 178 and 180 andthe second foil 195 is composed of sections 179 and 181. A capacitanceas illustrated by capacitor 190 is established between sections 178 and179. The parallel coils of sections 178 and 179 are interwoven as inFIG. 4, but are shown separated for the sake of simplicity in FIG. 8.Capacitance 190 represents the total capacitance established betweensections 178 and 179. Similarly, capacitor 191 represents thecapacitance established between sections 180 and 181. The dielectric isthe thinnest between sections 178 and 179 and the thickest betweensections 180 and 181. The first section 178 is connected through aterminal. 183 to a load terminal 203 of a load 200. The second endsection 180 of the first foil 194 is connected in series with the firstend section 178. The second end section 181 is wound in series with afirst end section 179. The first end section 179 is connected through aterminal 182 to a second load terminal 202.

Assuming the load to be a negative resistance device requiring a highstarting voltage, the initial impedance of the load will be very high.Therefore, the impedance between terminals 182 and 183 will beessentially an open circuit. Under open circuit conditions, the inducedvoltages of the first foil 194 and the second foil 195 will circulatecurrent through capacitors 190 and 191. The open circuit voltage thatappears across terminals 182 and 183 will be the sum of the inducedvoltage of sections 178 and the voltage developed across capacitor 190due to the aforesaid circulating current. This voltage ignites thedevice. After ignition, the impedance of the device is reduced andcurrent to operate the device flows between terminals 182 and 183. Thevoltage across terminals 182 and 183 is reduced from the open circuitvalue to an operating value. Current continues to circulate throughcapacitors 190 and 191 in accordance with Kirchhoffs Laws.

The amount of current circulating during operation is different than theamount of current circulating during open circuit conditions. This iscaused by the change in voltage across capacitors 190 and 191.

The voltages of the circuit shown in FIG. 8 occur in a manner similar tothe voltages shown in FIG. 6. The

voltage between the first end sections 178 and 179 is I less than thevoltage between the second end sections,

Therefore, a thinner dielectric can be used between sections 178 and 179than can be used between sections 180 and 181. The thinner dielectricincreases the capacitance between the first end sections 178 and 179.The capacitance of the winding in FIG. 8 has been increased over a priorart winding by the process of interweaving parallel coils and usingthinner dielectrics between the parallel coils in the first end sections178 and 179.

The invention as disclosed in this specification accomplishes theobjectives set forth for an improved capacitive inductive winding andadvances the art of construction of these windings. Combining theconcepts of parallel interwoven coils to replace a single thick foil andthe concept of changing dielectrics or gradients within the winding.Either one of the two con- 1 cepts of parallel interwoven coils orchanging the dielectric or dielectric thickness can be usedindependently of one another. Depending upon the application of thecapacitive inductive winding, one or both of the concepts can be used toimprove a winding over that of the prior art. However, the windingobtains the acme of refinement when both parallel interwoven coils andchanging dielectric or dielectric thickness are used simultaneously.

Although this invention has been described in its preferred form with acertain degree of particularity, it is understood that the presentdisclosure of the preferred form has been made only by way of exampleand that numerous changes in the details of the circuit and thecombination and arrangement of circuit elements may be resorted to.without departing from the spirit and scope of the invention ashereinafter claimed.

What is claimed is:

1. A capacitive inductive winding, comprising in combination,

first and second foil means each having first and second end sections,

means establishing a larger current carrying ability at I said first endsections than at said second end sections of each of said first andsecond foil means,

and graded capacitance means establishing a larger said first endsection of said first foil means and flows out of said first end sectionof said second foil means.

3. A capacitive inductive winding as set forth in claim 1, wherein saidmeans establishing a larger current carrying ability at said first endsections than at said second end sections includes a largercross-sectional area at said first end sections than at said second endsections.

4. A capacitive inductive winding as set forth in claim 1, wherein saidgraded capacitance means includes means establishing a larger effectivesurface area at said first end sections than at said second endsections.

5. A capacitive inductive winding as set forth in claim 1, wherein saidfirst and second foil means are interleaved when said foils are rolledinto a winding.

6. A capacitive inductive winding as set forth in claim 1, wherein saidfirst and second foil means are separated by dielectric means.

7. A capacitive inductive winding as set forth in claim 1, wherein eachof said first and second foil means has only three sections.

8. A capacitive inductive winding as set forth in claim 1, wherein saidfirst and second foil means are each composed of a plurality of seriessections.

9. A capacitive inductive winding as set forth in claim 1, wherein saidfoil means has a total of 28 sections and wherein S is any positiveinteger,

said first foil means composed of S odd numbered integer sections,

said second foil means composed of S even numbered integer sections,

said odd and even numbered integer sections one and two having S coilsconnected in parallel and being said first end sections of said firstand second foil means, respectively, said odd and even numbered integersections three and four having (S-l) coils connected in parallel,

the odd numbered integer sections being defined by the expression (ZN-l)having (S+lN) coils connected in parallel where N is a positive integernot greater than S,

the even numbered integer sections being defined by the expression (2N)having (S+lN) coils connectedin parallel,

said odd numbered integer section (2Sl) having a coil and being saidsecond end section of said first foil,

said even numbered integer sections (28) having a coil and being saidsecond end section of said second foil,

and said graded capacitance means includes interwoven sections having anequal number of coils connected in parallel and having said first andsecond foil means interleaved.

10. A capacitive inductive winding as set forth in claim 4, wherein saidmeans establishing a larger effective surface area includes said firstend sections being composed of only two coils connected in parallel.

11. A capacitive inductive winding as set forth in claim 4, wherein saidgraded capacitance means includes interwoven coils and interleavedfoils.

12. A capacitive inductive winding as set forth in claim 6, wherein saidgraded capacitance means includes means increasing the ratio of K,/Dwhere K is the dielectric constant and D is the thickness of saiddielectric means.

13. A capacitive inductive winding as set forth in claim 6, wherein saidgraded capacitance means includes means increasing the ratio of K/D,where K is the dielectric constant and D is the thickness of saiddielectric means and means establishing a larger effective surface areaA.

14. A capacitive inductive winding as set forth in claim 6, wherein saidgraded capacitance means includes means establishing a larger efiectivesurface area and means changing said dielectric means.

15. A capacitive inductive winding asset forth in claim 8, wherein saidfirst and second foil means are composed of coils connected in parallel.

16. A capacitive inductive winding as set forth in claim 8, includingmeans producing a variable magnetic flux, and

said first and second foil means being located within said varyingmagnetic flux to induce a voltage into said foil means.

17. A capacitive inductive winding as set forth in claim 14, whereinsaid means establishing a larger effective surface area includessections composed of coils connected in parallel,

and said means changing said dielectric means includes a thinnerdielectric means separating said first end sections than separating saidsecond end sections.

18. A capacitive inductive winding as set forth in claim 17, wherein thenumber of said parallel coils is related to the thickness of saiddielectric means to establish substantially uniform current density tothe input to said sections.

19. A capacitive inductive winding as set forth in claim 18, whereineach of said coils has substantially the same cross-sectional area. Y

20. A capacitive inductive winding as set forth in claim 16, including afirst and a second load terminal,

means connecting said first load terminal to said first end section ofsaid first foil means,

and means connecting said second load terminal to said first end sectionof said second foil means.

21. A capacitive inductive winding as set forth in claim 16, whereinsaid means producing a varying magnetic flux includes a primary windingand a magnetic core.

22. A capacitive inductive winding as set forth in claim 6, wherein thevoltage between said first end sections is less than the voltage betweensaid second end sections and the thickness of said dielectric means isless at said first end sections than at said second end sections.

A 23. A capacitive inductive winding, comprising in combination,

first and second foil means each having first and second end sections,

dielectric means separating said first and second foil means,

graded capacitance means establishing a larger capacitance between saidfirst end sections of said first and second foil means than at saidsecond end sections of said foil means,

and said graded capacitance means including a change in said dielectricmeans at said first end claim 23, wherein said changed dielectric meansincludes means increasing the dielectric constantof said dielectricmeans.

27. A capacitive inductive winding as set forth in claim 25, wherein thevoltage between said first end sections is less than the voltage betweensaid second end sections.

28. A capacitive inductive winding as set forth in claim 1, wherein saidfirst end sections of said first and second foil means are adjacent toone another.

1. A capacitive inductive winding, comprising in combination, first andsecond foil means each having first and second end sections, meansestablishing a larger current carrying ability at said first endsections than at said second end sections of each of said first andsecond foil means, and graded capacitance means establishing a largercapacitance between said first end sections of said first and secondfoil means than between said second end sections of said foil means. 2.A capacitive inductive winding as set forth in claim 1, wherein currentat a given instant flows into said first end section of said first foilmeans and flows out of said first end section of said second foil means.3. A capacitive inductive winding as set forth in claim 1, wherein saidmeans establishing a larger current carrying ability at said first endsections than at said second end sections includes a largercross-sectional area at said first end sections than at said second endsections.
 4. A capacitive inductive winding as set forth in claim 1,wherein said graded capacitance means includes means establishing alarger effective surface area at said first end sections than at saidsecond end sections.
 5. A capacitive inductive winding as set forth inclaim 1, wherein said first and second foil means are interleaved whensaid foils are rolled into a winding.
 6. A capacitive inductive windingas set forth in claim 1, wherein said first and second foil means areseparated by dielectric means.
 7. A capacitive inductive winding as setforth in claim 1, wherein each of said first and second foil means hasonly three sections.
 8. A capacitive inductive winding as set forth inclaim 1, wherein said first and second foil means are each composed of aplurality of series sections.
 9. A capacitive inductive winding as setforth in claim 1, wherein said foil means has a total of 2S sections andwherein S is any positive integer, said first foil means composed of Sodd numbered integer sections, said second foil means composed of S evennumbered integer sections, said odd and even numbered integer sectionsone and two having S coils connected in parallel and being said firstend sections of said first and second foil means, respectively, said oddand even numbered integer sections three and four having (S-1) coilsconnected in parallel, the odd numbered integer sections being definedby the expression (2N-1) having (S+1-N) coils connected in parallelwhere N is a positive integer not greater than S, the even numberedinteger sections being defined by the expression (2N) having (S+1-N)coils connected in parallel, said odd numbered integer section (2S-1)having a coil and being said second end section of said first foil, saideven numbered integer sections (2S) having a coil and being said secondend section of said second foil, and said graded capacitance meansincludes interwoven sections having an equal number of coils connectedin parallel and having said first and second foil means interleaved. 10.A capacitive inductive winding as set forth in claim 4, wherein saidmeans establishing a larger effective surface area includes said firstend sections being composed of only two coils connected in parallel. 11.A capacitive inductive winding as set forth in claim 4, wherein saidgraded capacitance means includes interwoven coils and interleavedfoils.
 12. A capacitive inductive winding as set forth in claim 6,wherein said graded capacitance means includes means increasing theratio of K,/D where K is the dielectric constant and D is the thicknessof said dielectric means.
 13. A capacitive inductive winding as setforth in claim 6, wherein said graded capacitance means includes meansincreasing the ratio of K/D, where K is the dielectric constant and D isthe thickness of said dielectric means and means establishing a largereffective surface area A.
 14. A capacitive inductive winding as setforth in claim 6, wherein said graded capacitance means includes meansestablishing a larger effective surface area and means changing saiddielectric means.
 15. A capacitive inductive winding as set forth inclaim 8, wherein said first and second foil means are composed of coilsconnected in parallel.
 16. A capacitive inductive winding as set forthin claim 8, including means producing a variable magnetic flux, and saidfirst and second foil means being located within said varying magneticflux to induce a voltage into said foil means.
 17. A capacitiveinductive winding as set forth in claim 14, wherein said meansestablishing a larger effective surface area includes sections composedof coils connected in parallel, and said means changing said dielectricmeans includes a thinner dielectric means separating said first endsections than separating said second end sections.
 18. A capacitiveinductive winding as set forth in claim 17, wherein the number of saidparallel coils is related to the thickness of said dielectric means toestablish substantially uniform current density to the input to saidsections.
 19. A capacitive inductive winding as set forth in claim 18,wherein each of said coils has substantially the same cross-sectionalarea.
 20. A capacitive inductive winding as set forth in claim 16,including a first and a second load terminal, means connecting saidfirst load terminal to said first end section of said first foil means,and means connecting said second load terminal to said first end sectionof said second foil means.
 21. A capacitive inductive winding as setforth in claim 16, wherein said means producing a varying magnetic fluxincludes a primary winding and a magnetic core.
 22. A capacitiveinductive winding as set forth in claim 6, wherein the voltage betweensaid first end sections is less than the voltage between said second endsections and the thickness of said dielectric means is less at saidfirst end sections than at said second end sections.
 23. A capacitiveinductive winding, comprising in combination, first and second foilmeans each having first and second end sections, dielectric meansseparating said first and second foil means, graded capacitance meansestablishing a larger capacitance between said first end sections ofsaid first and second foil means than at said second end sections ofsaid foil means, and said graded capacitance means including a change insaid dielectric means at said first end sections relative to saiddielectric means at said second end sections.
 24. A capacitive inductivewinding as set forth in claim 23, wherein said changed dielectric meansincludes means increasing the ratio of dielectric constant to thicknessof said dielectric means.
 25. A capacitive inductive winding as setforth in claim 23, wherein said changed dielectric means includes athinner dielectric means separating said first end sections thanseparating said second end sections.
 26. A capacitive inductive windingas set forth in claim 23, wherein said changed dielectric means includesmeans increasing the dielectric constant of said dielectric means.
 27. Acapacitive inductive winding as set forth in claim 25, wherein thevoltage between said first end sections is less than the voltage betweensaid second end sections.
 28. A capacitive inductive winding as setforth in claim 1, wherein said first end sections of said first andsecond foil means are adjacent to one another.